forms - Symfony 2 subform not bindig data

Question

I have a form that is not directly related to a doctrine entity but some of his subforms are

public function buildForm(FormBuilderInterface $builder, array $options)
  {
      $builder
          ->add('Email','email')
          ->add('ShippingAddress',new AddressType($this->Order->getStore()))
          ->add('SameAddress','checkbox',array('required' => false))
          ->add('BillingAddress',new AddressType($this->Order->getStore()))
          ->setData(array('Email' => $this->Order->getEmail(),
                          'ShippingAddress' => $this->Order->getShippingAddress(),                                                                                                                                                                 
                          'BillingAddress' => $this->Order->getBillingAddress()))
      ;
 }

the first time I post the form

$billingAddress = $formstep1->get('BillingAddress')->getData();

returns the correct data from the fields and can be saved when I try to edit the form the Shipping and Billing forms return preseted data

but if i access to the field inside this forms I get the corrrect data $formstep1->get('ShippingAddress')->get('LastNames')->getData());

Why is this happening?

Can't I set data in builForm and expect the form to bind data to this objects ?

Thanks